Uni-Ball Signo RT1 UMN155-05 Gel Ink Rollerball Pen 0.5mm Baby Pink Box of 10
Uni-Ball Signo RT1 UMN155-05 Gel Ink Rollerball Pen 0.5mm Baby Pink Box of 10
Uni-Ball Signo RT1 UMN155-05 Gel Ink Rollerball Pen 0.5mm Baby Pink Box of 10
Uni-Ball Signo RT1 UMN155-05 Gel Ink Rollerball Pen 0.5mm Baby Pink Box of 10
Uni-Ball Signo RT1 UMN155-05 Gel Ink Rollerball Pen 0.5mm Baby Pink Box of 10
Uni-Ball Signo RT1 UMN155-05 Gel Ink Rollerball Pen 0.5mm Baby Pink Box of 10
Uni-Ball Signo RT1 UMN155-05 Gel Ink Rollerball Pen 0.5mm Baby Pink Box of 10
Uni-Ball Signo RT1 UMN155-05 Gel Ink Rollerball Pen 0.5mm Baby Pink Box of 10
Uni-Ball Signo RT1 UMN155-05 Gel Ink Rollerball Pen 0.5mm Baby Pink Box of 10
Uni-Ball Signo RT1 UMN155-05 Gel Ink Rollerball Pen 0.5mm Baby Pink Box of 10
Uni-Ball Signo RT1 UMN155-05 Gel Ink Rollerball Pen 0.5mm Baby Pink Box of 10
Uni-Ball Signo RT1 UMN155-05 Gel Ink Rollerball Pen 0.5mm Baby Pink Box of 10
Uniball

Uni-ball Signo RT1 UMN155-05 Retractable Gel Ink Rollerball Pen 0.5mm Baby Pink Box of 10

Regular price
$22.46
Sale price
$22.46
Regular price
RRP $23.87
Or 4 payments of $5.62 with
Add items to a quote for bulk pricing, approvals, or purchase orders.

SKU: UMUMN155-05BP

UPC: 34902778142777

MPN: UMN155-05BP

Baby Pink, the Palest Ink in the Range

Baby pink is the lightest of the colours we stock in the uni-ball Signo RT1, a retractable gel ink pen that uni-ball's 2026 catalogue publishes at a 0.5mm line width.

A pale ink behaves differently from a dark one. It sits lightly on the page, which is what makes it useful for underlining and for notes meant to stay visually behind the text they annotate. It is also why width matters here more than in the darker colours: at 0.5mm there is enough ink laid down for a light colour to read, where a narrower tip would thin it further.

uni-ball publishes the RT1 as retractable, and the ink as gel ink. The group code is UMN-155, with this width written UMN155-05 on uni-ball's site. Baby Pink is the store's own name for the variant, from our supplier data, since uni-ball does not publish colour names as text for this model.

The darker colours in the same width, and the 0.38mm version of this pen, are at gel pens. The brand range is at uni-ball, other pens at pens, and the rest at writing supplies.

  • Retractable, as published by uni-ball for the Signo RT1
  • Gel ink, described on uni-ball's own page as new improved gel ink
  • 0.5mm line width, published in uni-ball's 2026 product catalogue rather than on the product page
  • Baby pink ink, the palest colour we stock in this range
  • uni-ball publishes the model under the group code UMN-155, this width as UMN155-05
  • Supplied as a box of 10, all one colour
  • Journalling, planners and bullet lists
  • Underlining and light annotation over printed text
  • Study notes layered over a darker first pass
  • Craft lettering and card writing
  • Colour-coded diaries where a soft tone is wanted

Shipping

Shipping is kept simple with flat rates for selected areas and free shipping where applicable. Large, bulky, rural or out-of-area orders may require additional freight, and our team will contact you if this applies. For a more specific estimate, simply add this product to a quote or visit our shipping page.

Delivery Times

Melbourne, Sydney, Brisbane, Adelaide — 1 to 3 business days
Perth — 1 to 5 business days
Regional & Outer Areas — 3 to 7 business days

Returns

If you have questions about returns, please contact us or visit our returns page for full details.

Specifications

Brand: uni-ball

Range: Signo RT1

Model Group: UMN-155

Manufacturer Code: UMN155-05

Mega Code: UMUMN155-05BP

Colour: Baby Pink

Line Width: 0.5mm (published in uni-ball's 2026 product catalogue, not on the product page)

Ink Type: Gel ink

Mechanism: Retractable

Pack: Box of 10

Barcode: 34902778142777

Refill Code: Not published by the manufacturer

Country Of Origin: Not published by the manufacturer

FAQs

uni-ball's product page for the Signo RT1 does not publish a tip size. The 0.5mm figure is published in uni-ball's 2026 product catalogue, which lists the model in three widths. We have attributed it to the catalogue rather than the page so you can see which source it rests on.
uni-ball publishes no refill code for the Signo RT1, so we are not going to name one. Other Signo models take their own specific refills and guessing across models is how the wrong cartridge gets ordered. Ask us and we will chase the code through the supplier.
For your own notes, yes. For anything someone else has to read at a distance, or anything that will be photocopied, a darker colour is the safer pick. Light inks are at their best annotating text rather than carrying it.
Retractable. uni-ball states that on its own product page for this model, which is why we are comfortable publishing it. There is no cap.
uni-ball is not consistent about it. The uni-ball website publishes this width as UMN155-05, while uni-ball's 2026 catalogue uses a different pattern for the family, writing the finer 0.38mm pen as UMN-155-38. The two sources do not spell the range the same way, so we have used the website spelling and flagged it rather than picking one silently.
Ten, all baby pink. That is the pack we hold against UMUMN155-05BP, read from this product's own record rather than assumed from the range.

Shipping & Delivery

Delivery time depends on your location, the size of your order, and the shipping option selected at checkout. For in-stock items, standard metro delivery in QLD, NSW and VIC is usually 1 to 7 business days. South Australia, Tasmania, Western Australia and the Northern Territory are generally 3 to 12 business days. Express delivery for eligible parcels under 3kg is usually 1 to 4 business days in QLD, NSW, ACT and VIC. Delivery estimates apply to in-stock items only and may vary due to carrier conditions or delays.

If you need to make a change to your order, please contact our team as soon as possible. Once an order has been processed or dispatched, changes may no longer be possible. You can contact us through our Contact Us page for assistance.

Mega Office Supplies ships orders Australia wide and occasionally internationally. The best avenue would be to contact us so we can customise a specific quote for you. Please note that associated international duties, taxes and levies will be the responsibility of the customer.

Returns, Refunds & Replacements

Mega Office Supplies accepts change-of-mind returns for unopened and unused products within 14 days from the invoice date, provided the item is returned in its original packaging and in resalable condition. Original shipping costs are not refundable, return shipping is the customer’s responsibility, and a restocking fee may apply depending on the product type and supplier. Some items, including electronics, assembled or installed furniture, food, beverages, medicines, custom-made products, and certain bulk or special-order items, are not eligible for return unless required under Australian Consumer Law.

If your order arrives faulty, damaged, or incorrect, please contact Mega Office Supplies as soon as possible. Where required under Australian Consumer Law, a repair, replacement, or refund will be offered. In these cases, Mega Office Supplies will cover reasonable return shipping costs, and photographic evidence may be requested to help process the claim. Items should be reported within a reasonable timeframe after delivery.